Mortality following substance use disorder treatment: population-based record-linkage retrospective cohort design


A. González-Santa Cruz 1, 2,

A. Castillo-Carniglia 1, 3,

1 Millennium Nucleus for the evaluation and analysis of Drug Policies
2 Ph.D. student, School of Public Health, Universidad de Chile
3 Department of Public Health, Facultad de Medicina y Ciencia, Universidad San Sebastián, Chile

Background

  • Chile has one of the highest alcohol consumption in the continent\(^{[1]}\)
  • In 2016, led in high school cocaine, coca paste, and marijuana use\(^{[2]}\)
  • Over 170% growth in drug-related mortality, 2000 vs 2019\(^{[3]}\)
  • In 2020, 6% of Chileans (12-64) had a problematic substance (alcohol & drug) use \(^{[4]}\)
  • In Chile, the government funds substance use treatments (SUT) for all with public health insurance (~81% of the population)\(^{[5]}\)
  • There is limited information regarding short-term, medium-term, and long-term mortality risks
  • Analyzing mortality among administrative regions may reveal disparities in post-treatment outcomes
  • Regional data can inform policy and resource allocation

Objectives

To describe the standardized mortality ratios (SMRs) for all adult patients in publicly funded SUT within 2010-2022, along with regional specificities

Methods

Design: a population-based retrospective cohort of adults enrolled in Chilean SUT programs (18-65) with national mortality data (2010-2020).

Analysis plan. We calculated SMRs by comparing the observed deaths vs. the expected within regions, age groups (18-29, 30-44, 45-59 & 60-65), periods (annually), and across sexes. Stratum-specific population estimates were obtained from the Ministry of Health’s mortality data, supplemented by population projections from the National Institute of Statistics’ open data portal\(^{[6]}\). Regional data on cocaine, marijuana, and hazardous alcohol use were obtained from the 2020 Chile National Drug Study by the National Drug and Alcohol Prevention and Rehabilitation Service. 95% confidence intervals(CIs) were calculated using Vandenbroucke’s method\(^{[7]}\).


Preliminary Results

Characteristics of SUT patients

Figure 1: Characteristics of SUT patients

.

Standardized mortality ratios for people in SUT, by age group and sex

Figure 2: Standardized mortality ratios for people in SUT, by age group and sex

.

Regional data in quartiles

Figure 3: Regional data in quartiles

The SMR in the SUT population was 15.5 (95%CI 15.0, 16.1) times higher than expected based on the general population. Women aged between 30-44 had a mortality risk up to 29.6 times (95%CI 26.0, 33.5) higher than expected.

Regions with high SMRs for men also have high SMRs for women. There were also regional variations in mortality risks post-SUT, but the regional prevalence of problematic substance use does not appear to be related to SMRs.

Discussion

  • High cumulative mortality risk in SUT patients vs. general population
  • Higher risk particularly among women
  • Largest sex gap at younger ages
  • Further exploration of substance use’s contribution to elevated risk
  • Mortality risks were higher in areas influenced by ethnic and cultural barriers, discrimination, or geographical isolation, which hinder access to treatment

References

[1] B. Vicente, S. Saldivia, and R. Pihán. “Prevalencias y brechas hoy: salud mental mañana”. In: Acta bioethica 22 (2016), pp. 51–61. ISSN: 1726-569X. DOI: 10.4067/S1726-569X2016000100006.

[2] Inter-American Drug Abuse Control Commission [CICAD]. Report on Drug Use in the Americas 2019: Executive Summary. Tech. rep. Washington, DC, 2019. URL: http://www.cicad.oas.org/cicaddocs/Document.aspx?Id=4976.

[3] OECD and World Bank. Health at a Glance: Latin America and the Caribbean 2023. 2023. DOI: https://doi.org/10.1787/532b0e2d-en. URL: https://www.oecd-ilibrary.org/content/publication/532b0e2d-en.

[4] Servicio Nacional para la Prevención y Rehabilitación del Consumo de Drogas y Alcohol [SENDA]. Décimo Cuarto Estudio Nacional de Drogas en Población General de Chile, 2020. Tech. rep. Santiago, Chile: Ministerio del Interior y Seguridad Pública, 2022. URL: https://www.senda.gob.cl/wp-content/uploads/2022/01/Estudio-PG2020.pdf.

[5] M. Mateo-Pinones, A. González-Santa Cruz, R. Portilla Huidobro, et al. “Evidence-based policymaking: Lessons from the Chilean Substance Use Treatment Policy”. In: International Journal of Drug Policy 109 (nov.. 2022), p. 103860. ISSN: 0955-3959. DOI: 10.1016/j.drugpo.2022.103860. URL: https://www.sciencedirect.com/science/article/pii/S0955395922002766.

[6] Instituto Nacional de Estadísticas [INE]. Tablas de Mortalidad de Chile 1992-2050: Documento Metodológico. ene.. 2023. URL: https://www.ine.gob.cl/docs/default-source/proyecciones-de-poblacion/metodologia/proyecci%C3%B3n-base-2017/tablas-de-mortalidad-de-chile-1992-2050-metodologia.pdf?sfvrsn=ff4b0f8a_5}.

[7] M. Szklo and F. J. Nieto. Epidemiology : beyond the basics. Fourth edition. Burlington, Mass: Jones & Bartlett Learning, 2019. ISBN: 978-1-4496-0469-1.

Funding sources

  • This work was funded by ANID - Millennium Science Initiative Program - N° NCS2021_003 (Castillo-Carniglia) and ANID - Doctoral Scholarship National Doctorate/2023-21230172 (González-Santa Cruz)

  • Correspondence to: Andrés González-Santa Cruz,

High Mortality in SUT Patients, particularly among women, and regional variations in mortality risks